Detailed Product Description ABT-30Photoelectric Beam, 2 Beams, 30M. Digital Frequency Conversion.ABT-60Photoelectric Beam, 2 Beams, 60M. Digital Frequency Conversion.ABT-80Photoelectric Beam, 2 Beams, 80M. Digital Frequency Conversion.ABT-100Photoelectric Beam, 2 Beams, 100M. Digital Frequency Conversion.